nEDM experiment at PSI: Data-taking strategy and sensitivity of the dataset

¹ Department of Physics and Astronomy, University of Sussex, Brighton, UK
² Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, Caen, France
³ Paul Scherrer Institute (PSI), Villigen, Switzerland
⁴ Marian Smoluchowski Institute of Physics, Jagiellonian University, Cracow, Poland
⁵ Instituut voor Kern – en Stralingsfysica, Katholieke Universiteit Leuven, Leuven, Belgium
⁶ Laboratory for High Energy Physics, Albert Einstein Center for Fundamental Physics, University of Bern, Bern, Switzerland
⁷ ETH Zürich, Institute for Particle Physics and Astrophysics, Zürich, Switzerland
⁸ Univ. Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, Grenoble, France
⁹ Institute of Nuclear Chemistry, Johannes Gutenberg University, Mainz, Germany
¹⁰ CSNSM, Université Paris Sud, CNRS/IN2P3, Université Paris Saclay, Orsay-Campus, France
¹¹ Physikalisch Technische Bundesanstalt, Berlin, Germany
¹² University of Fribourg, Fribourg, Switzerland

^a e-mail: ferraris@lpsc.in2p3.fr
^b Present address: Max-Planck-Institute für Kernphysik, Heidelberg, Germany
^c Present address: Massachusetts Institute of Technology, Cambridge, MA, USA
^d Present address: Michigan State University, East-Lansing, USA
^e e-mail: roccia@csnsm.in2p3.fr, present address: Institut Laue-Langevin, Grenoble, France
^f e-mail: philipp.schmidt-wellenburg@psi.ch

Published online: 12 December 2019

Abstract

We report on the strategy used to optimize the sensitivity of our search for a neutron electric dipole moment at the Paul Scherrer Institute. Measurements were made upon ultracold neutrons stored within a single chamber at the heart of our apparatus. A mercury cohabiting magnetometer together with an array of cesium magnetometers were used to monitor the magnetic field, which was controlled and shaped by a series of precision field coils. In addition to details of the setup itself, we describe the chosen path to realize an appropriate balance between achieving the highest statistical sensitivity alongside the necessary control on systematic effects. The resulting irreducible sensitivity is better than 1 × 10⁻²⁶e cm. This contribution summarizes in a single coherent picture the results of the most recent publications of the collaboration.